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EEE (midterms) > mod 6 > Flashcards

mod 6 Flashcards

1
Q

are also called alternators. Almost all electric power for homes and industry is supplied by alternators in power plants.

A

ALTERNATING-CURRENT GENERATORS

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2
Q

It has the same function as DC generators. They produce alternating current that is then converted to direct current before it enters an aircraft’s electrical system.

A

DC ALTERNATORS

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3
Q

Capable of producing a great deal of power and, therefore, typically found on larger aircraft and military aircraft.

A

AC ALTERNATORS

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4
Q

It is similar in construction to the DC generator, in that the armature rotates within a stationary magnetic field.

A

REVOLVING-ARMATURE TYPE ALTERNATOR

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5
Q

It has a stationary armature winding (stator) and a rotating-field winding (rotor). The advantage of this configuration is that the armature is connected directly to the load without sliding contacts in the load circuit.

A

REVOLVING-FIELD TYPE ALTERNATOR

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6
Q

consists of a wire coil wound on an iron spool between two heavy iron segments with interlacing fingers.

A

ALTERNATOR ROTOR

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7
Q

is a circular unit that surrounds the rotor. It is made up of wire coils around an iron housing.

A

STATOR

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8
Q

In a _____, the stator is made up of several windings connected in series to form a single circuit.

A

SINGLE-PHASE ALTERNATOR

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9
Q

_____ have two or more single-phase windings spaced symmetrically around the stator, so that the AC voltage induced in one is 90° out of phase with the voltage induced in the other.

A

TWO-PHASE ALTERNATOR

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10
Q

Also called a polyphase alternator, it has three single phase windings spaced so that the voltage induced in each winding is 120° out of phase with the voltage in the other two windings.

A

THREE-PHASE ALTERNATOR

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11
Q

depends on the number of field poles and on the speed at which the generator is operated.

A

FREQUENCY

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12
Q

generator is the percentage rise in terminal voltage as load is reduced from the rated full-load current to zero, with the speed and excitation being constant.

A

VOLTAGE REGULATION

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13
Q

Most power plants have several ac generators operating in parallel in order to increase the power available. Before two generators may be paralleled, their terminal voltages must be equal, their voltages must be in phase, and their frequencies must be equal. When these conditions are met, the two generators are operating in synchronism.

A

PARALLELING GENERATORS

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14
Q

The operation of getting the generators into synchronism is called ______.

A

SYNCHRONIZING

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15
Q

_____ of an ac generator are similar to those of a dc generator and include armature copper loss, field-excitation copper loss, and mechanical losses.

A

LOSSES

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16
Q

The _____ consists of a frame (or yoke) and two end brackets (or bearing housings). A motor’s _____ not only holds the motor components together, it also protects the internal components from moisture and containment.

A

ENCLOSURE

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16
Q

_____ is the ratio of the useful power output to the total power input.

A

EFFICIENCY

17
Q

_____ permit cooling air to flow through the motor. One type of _____ is the open drip proof (ODP) enclosure.

A

OPEN CLOSURE

18
Q

A _____ (TENV) motor enclosure limits the flow of air into the motor, but is not airtight.

A

TOTALLY ENCLOSED NON-VENTILATED ENCLOSURE

19
Q

A _____ (TEFC) motor is similar to a TENV motor, but has an external fan mounted opposite the drive end of the motor.

A

TOTALLY ENCLOSED FAN-COOLED ENCLOSURE

20
Q

Hazardous duty applications are commonly found in chemical processing, mining, foundry, pulp and paper, waste management, and petrochemical industries.

A

EXPLOSION-PROOF ENCLOSURE

21
Q

The motor _____ consists of two main parts: _____ core and _____windings. The _____ core is made up of many thin metal sheets, called laminations. Laminations are used to reduce energy losses that would result if a solid core were used.

A

STATOR

22
Q

The _____ is the rotating part of the motor electromagnetic circuit.

A

ROTOR

23
Q

Motor _____ are mounted on the shaft and support the rotor to turn. Not all _____ are suitable for every application.

A

BEARINGS

24
Q

is a metal box on a motor which protects one or more terminals or terminal boards.

A

CONDUIT BOX

25
Q

are so called because their field windings are connected directly to a single- phase source.

A

SINGLE-PHASE MOTORS

26
Q

Also known as the universal motor. When an ordinary dc series motor is connected to an ac supply, the current drawn by the motor is low due to the high series-field impedance.

A

AC SERIES MOTOR

26
Q

The _____ has an armature and commutator similar to that of a dc motor. However, the brushes are not connected to the supply but are short-circuited.

A

REPULSION MOTOR

27
Q

-A single-phase induction motor is not self-starting. The magnetic field set up in the stator by the ac power supply stays lined up in one direction. This magnetic field, though stationary, pulsates as the voltage sine wave does.

A

INDUCTION MOTOR

28
Q

If two stator windings of unequal impedance are spaced 90 degrees apart but connected in parallel to a single-phase source, the field produced will appear to rotate. This is the principle of phase splitting.

A

SPLIT-PHASE MOTOR

29
Q

By placing a capacitor in series with the starting winding of a split-phase motor, starting characteristics are improved. The current in the starting winding may be made to lead the voltage.

A

CAPACITOR START MOTOR

30
Q

The _____ operates with an auxiliary winding and series capacitor permanently connected to the line.

A

PERMANENT CAPACITOR MOTOR

31
Q

Like a dc motor, the rotor of the repulsion- start induction motor has windings connected to a commutator.

A

REPULSION START INDUCTION MOTOR

32
Q

A _____ is produced by a short-circuited coil wound around a part of each pole of a motor

A

SHADED-POLE MOTOR

33
Q

Several types exist to drive electric clocks, phonograph turntables, and other devices requiring precise rotation

A

SYNCHRONOUS MOTOR

34
Q

The _____ is the most commonly used type of ac motor because of its simple, rugged construction and good operating characteristics. It consists of two parts: the stator (stationary part) and the rotor (rotating part).

A

INDUCTION MOTORS

35
Q

The rotor of a _____ has a laminated core, with conductors placed parallel to the shaft and embedded in slots around the perimeter of the core.

A

SQUIRREL-CAGE MOTOR

36
Q

The rotor of a _____ is wound with an insulated winding similar to the stator winding.

A

WOUND ROTOR MOTOR

37
Q

Like induction motors, _____ have stator windings that produce a rotating magnetic field. But unlike the induction motor, the rotor circuit of a _____ is excited by a dc source.

A

SYNCHRONOUS MOTORS

38
Q

The speed of the rotating magnetic field is called the synchronous speed of the motor

A

SPEED AND SLIP

39
Q

-For any value of slip, the_____ is equal to the stator frequency times the percent slip.

A

ROTOR FREQUENCY

40
Q

depends on the strength of the interacting rotor and stator fields and the phase relations between them.

A

TORQUE

EEE (midterms) (3 decks)

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